Examining Risks to Honey Bee Pollinators Foraging in Agricultural Landscapes

Bee pollinators provide essential ecological services to wild plant communities, and addtremendous economic value to agriculture by improving both the quality and quantity of crop yield. Beekeepers are often contracted by growers to provide colonies of honey bees for pollination of high-value produce (fruits, vegetables and nuts). Many of the major commodity crops produced in the central and mid-southern United States are wind-pollinated (rice, corn, grain sorghum, wheat), or are sufficiently self-fertile (soybeans, cotton), and so do not require bee pollination in order to produce yield. Beekeepers still rely on these agricultural landscapes to support honey bee colonies when not actively pollinating farms or orchards because these landscapes remain irrigated and productive while other areas may endure a long seasonal nectar dearth. However, intensely managed agricultural landscapes can also expose bees to a variety of detrimental risks, including reduced plant diversity and nutrition, and increased pesticide exposure. Neonicotinoid insecticides have been blamed for recent widespread losses of honey bee colonies in the U.S. and abroad. The planting of insecticide-coated seeds to protect plant growth from early season insect damage has come under particular scrutiny as a potentially significant factor in honey bee declines. Previous investigations have concluded with inconsistent results, based on varying methods employed, seasons and environments, and the scale of the experiments. This study characterized the landscape where seed treatments were common, in terms of floral resources available to bees, sources of contamination. A radius of 2 miles (3.2 km) around an apiary was surveyed for 2 seasons to determine the land use by crop, and to quantify the proportion planted with treated seeds, and what other products were applied during the cropping season, and which of these compounds were found in bee hives. Our survey found that approximately 81% of the landscape was under cultivation, of which 70% was planted with neonicotinoid treated seeds. However, no neonicotinoids were detected in samples of bee hive products. Because pollen could be sampled directly from foraging bees at discrete intervals, and traced back to plant origin, it was used as a bioindicator to determine when neonicotinoids might be present in crops or wild plants. Bees collected relatively little pollen from crops except for a brief period of hot, dry weather. Neonicotinoids were detected infrequently and at low levels, and not at all when bees were visiting crop plants. To test the effects of neonicotinoid ingestion on individual bees in situ, a method was devised to continuously monitor the activities of individual honey bees fed with a sublethal concentration of imidacloprid. Bees that consumed 20 ppb imidacloprid did not suffer acute mortality, but actually appeared to survive 1.7 times as long as untreated bees. This work suggests that neonicotinoids, when properly utilized, may not necessarily pose a greater risk to honey bees than other agricultural chemicals, provided colonies have access to sufficient alternative nutritional sources in the surrounding landscape

Future Ocean Observations to Connect Climate, Fisheries and Marine Ecosystems

Advances in ocean observing technologies and modeling provide the capacity to revolutionize the management of living marine resources. While traditional fisheries management approaches like single-species stock assessments are still common, a global effort is underway to adopt ecosystem-based fisheries management (EBFM) approaches. These approaches consider changes in the physical environment and interactions between ecosystem elements, including human uses, holistically. For example, integrated ecosystem assessments aim to synthesize a suite of observations (physical, biological, socioeconomic) and modeling platforms [ocean circulation models, ecological models, short-term forecasts, management strategy evaluations (MSEs)] to assess the current status and recent and future trends of ecosystem components. This information provides guidance for better management strategies. A common thread in EBFM approaches is the need for high-quality observations of ocean conditions, at scales that resolve critical physical-biological processes and are timely for management needs. Here we explore options for a future observing system that meets the needs of EBFM by (i) identifying observing needs for different user groups, (ii) reviewing relevant datasets and existing technologies, (iii) showcasing regional case studies, and (iv) recommending observational approaches required to implement EBFM. We recommend linking ocean observing within the context of Global Ocean Observing System (GOOS) and other regional ocean observing efforts with fisheries observations, new forecasting methods, and capacity development, in a comprehensive ocean observing framework

Comprehensive Survey of Area-Wide Agricultural Pesticide Use in Southern United States Row Crops and Potential Impact on Honey Bee Colonies

Honey bees forage across a large area, continually scouting the local landscape for ephemeral food resources. Beekeepers often rely on flowering plants in and around irrigated farmland to maintain their colonies during dry seasons, despite the potential risk of pesticide exposure. Recent declines in pollinator abundance and diversity have focused attention on the role of pesticides and their effects on honey bee health. This investigation examined two types of landscapes within a two-mile (3.2 km) radius of honey bee colonies: an intensive agricultural setting and a rural setting without intensive agriculture. More than 10,000 acres of agricultural land was surveyed to quantify the area of cultivated crops and the area treated with pesticides, including seed treatments and foliar applications of insecticides. Samples of honey, bee bread (stored pollen), beeswax, and adult bees were collected from hives in both landscape types and screened for pesticide residues to determine if foraging bees were transporting pesticides to hives. Some samples of bee bread and honey did contain pesticide residues, but these were below known lethal dose (LD50) levels for honey bees. Beeswax samples contained the highest levels of contamination, but most were still relatively low. Samples were screened for 174 common agricultural pesticides and metabolites, but only 26 compounds were detected during the two-year study. These included one defoliant, one insect growth regulator, five herbicides, six fungicides, six insecticides never used in beekeeping, and five insecticides/miticides and their metabolites, which are used in beekeeping and for various other agricultural purposes, as well as two miticides exclusively used by beekeepers to control Varroa destructor. Bee colonies foraging in agricultural landscapes are potentially exposed to numerous pesticide applications. While the residues detected in this study did not pose an acute lethal risk to adult honey bees, this study did not measure sublethal effects on bee colony health or performance, which merit further investigation

Sublethal Effects of Imidacloprid on Honey Bee Colony Growth and Activity at Three Sites in the U.S.

<div><p>Imidacloprid is a neonicotinoid pesticide heavily used by the agricultural industry and shown to have negative impacts on honey bees above certain concentrations. We evaluated the effects of different imidacloprid concentrations in sugar syrup using cage and field studies, and across different environments. Honey bee colonies fed sublethal concentrations of imidicloprid (0, 5, 20 and 100 ppb) over 6 weeks in field trials at a desert site (Arizona), a site near intensive agriculture (Arkansas) and a site with little nearby agriculture but abundant natural forage (Mississippi) were monitored with respect to colony metrics, such as adult bee and brood population sizes, as well as pesticide residues. Hive weight and internal hive temperature were monitored continuously over two trials in Arizona. Colonies fed 100 ppb imidacloprid in Arizona had significantly lower adult bee populations, brood surface areas and average frame weights, and reduced temperature control, compared to colonies in one or more of the other treatment groups, and consumption rates of those colonies were lower compared to other colonies in Arizona and Arkansas, although no differences in capped brood or average frame weight were observed among treatments in Arkansas. At the Mississippi site, also rich in alternative forage, colonies fed 5 ppb imidacloprid had less capped brood than control colonies, but contamination of control colonies was detected. In contrast, significantly higher daily hive weight variability among colonies fed 5 ppb imidacloprid in Arizona suggested greater foraging activity during a nectar flow post treatment, than any other treatment group. Imidacloprid concentrations in stored honey corresponded well with the respective syrup concentrations fed to the colonies and remained stable within the hive for at least 7 months after the end of treatment.</p></div

Coumaphos and imidacloprid concentrations, in ppb, detected in honey and adult bees before start of treatment (16 July) and after 32 days (17 Aug.) in Mississippi with respect to treatment group.

<p>Coumaphos and imidacloprid concentrations, in ppb, detected in honey and adult bees before start of treatment (16 July) and after 32 days (17 Aug.) in Mississippi with respect to treatment group.</p

Post hoc comparisons for two field experiments conducted in Arizona.

<p>Post hoc comparisons for two field experiments conducted in Arizona.</p

Imidacloprid concentrations, in ppb, in adult bees, honey, pollen and wax after exposure of bee colonies to imidacloprid in sugar syrup in Arkansas.

<p>Imidacloprid concentrations, in ppb, in adult bees, honey, pollen and wax after exposure of bee colonies to imidacloprid in sugar syrup in Arkansas.</p